1. Field of the Invention
The present invention relates to a hard coating film and a method for forming the same. The hard coating film is designed to improve the wear resistance of cutting tools (such as tip, drill, and end mill) and jigs (such as forging die and punching die).
2. Description of the Related Art
Coating with a hard film of TiN, TiCN, TiAlN or the like has been a conventional way of improving the wear resistance of cutting tools made of cemented carbide, cermet, or high-speed steel. It has recently been found that a coating film of TiAlN (which is a composite nitride of Ti and Al) excels in wear resistance, as disclosed in Patent Document 1 below. This coating film is finding use in the field of cutting tools for high-speed cutting and hard materials such as hardened steel, in place of the coating film of titanium nitride, carbide, or carbonitride. Another recent development is a coating film of laminate structure composed of layers differing in crystal structure and composition for improved wear resistance (as disclosed in Patent Document 2 below) or a coating film of TiAlSiN incorporated with Cr for improved hardness and oxidation resistance (as disclosed in Patent Document 3 below).    Patent Document 1:            Japanese Patent No. 2644710            Patent Document 2:            Japanese Patent Laid-open No. 2005-213637            Patent Document 3:            Japanese Patent Laid-open No. 2003-71611        